Thermal stresses in orthotropic plates with a variable heat transfer coefficient

1972 ◽  
Vol 8 (1) ◽  
pp. 42-46 ◽  
Author(s):  
Yu. M. Kolyano ◽  
V. I. Gromovyk
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Thermal Stresses ◽  
Orthotropic Plates ◽  
Variable Heat

scholarly journals The use of a solution of the inverse heat conduction problem to monitor thermal stresses

2019 ◽  
Vol 108 ◽  
pp. 01003
Author(s):  
Jan Taler ◽  
Piotr Dzierwa ◽  
Magdalena Jaremkiewicz ◽  
Dawid Taler ◽  
Karol Kaczmarski ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Power Plants ◽  
Thermal Stresses ◽  
Thermal Power ◽  
Temperature Fields ◽  
Thick Wall ◽  
Fluid Temperature ◽  
Unsteady Temperature

Thick-wall components of the thermal power unit limit maximum heating and cooling rates during start-up or shut-down of the unit. A method of monitoring the thermal stresses in thick-walled components of thermal power plants is presented. The time variations of the local heat transfer coefficient on the inner surface of the pressure component are determined based on the measurement of the wall temperature at one or six points respectively for one- and three-dimensional unsteady temperature fields in the component. The temperature sensors are located close to the internal surface of the component. A technique for measuring the fastchanging fluid temperature was developed. Thermal stresses in pressure components with complicated shapes can be computed using FEM (Finite Element Method) based on experimentally estimated fluid temperature and heat transfer coefficient

Identification of three-dimensional transient temperature fields in thick-walled elements using the inverse method

2018 ◽  
Vol 28 (1) ◽  
pp. 138-150 ◽  
Author(s):  
Magdalena Jaremkiewicz
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Inverse Method ◽  
Thermal Stresses ◽  
Computing Time ◽  
Transient Temperature ◽  
Content Type ◽  
Inner Surface ◽  
The Heat Transfer Coefficient

Purpose The purpose of this paper is to propose a method of determining the transient temperature of the inner surface of thick-walled elements. The method can be used to determine thermal stresses in pressure elements. Design/methodology/approach An inverse marching method is proposed to determine the transient temperature of the thick-walled element inner surface with high accuracy. Findings Initially, the inverse method was validated computationally. The comparison between the temperatures obtained from the solution for the direct heat conduction problem and the results obtained by means of the proposed inverse method is very satisfactory. Subsequently, the presented method was validated using experimental data. The results obtained from the inverse calculations also gave good results. Originality/value The advantage of the method is the possibility of determining the heat transfer coefficient at a point on the exposed surface based on the local temperature distribution measured on the insulated outer surface. The heat transfer coefficient determined experimentally can be used to calculate thermal stresses in elements with a complex shape. The proposed method can be used in online computer systems to monitor temperature and thermal stresses in thick-walled pressure components because the computing time is very short.

Experimental and numerical analysis of a plate heat exchanger using variable heat transfer coefficient

2021 ◽  
pp. 1-19
Author(s):  
Muhammad Ahmad Jamil ◽  
Talha S. Goraya ◽  
Haseeb Yaqoob ◽  
Muhammad Wakil Shahzad ◽  
Syed M. Zubair
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Numerical Analysis ◽  
Transfer Coefficient ◽  
Plate Heat Exchanger ◽  
Plate Heat ◽  
Variable Heat

scholarly journals Online Determining Heat Transfer Coefficient for Monitoring Transient Thermal Stresses

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 704
Author(s):  
Magdalena Jaremkiewicz ◽  
Jan Taler
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Thermal Stresses ◽  
Thermal Power ◽  
Computer Calculation ◽  
Transient Temperature ◽  
Unsteady Temperature ◽  
The Heat Transfer Coefficient

This paper proposes an effective method for determining thermal stresses in structural elements with a three-dimensional transient temperature field. This is the situation in the case of pressure elements of complex shapes. When the thermal stresses are determined by the finite element method (FEM), the temperature of the fluid and the heat transfer coefficient on the internal surface must be known. Both values are very difficult to determine under industrial conditions. In this paper, an inverse space marching method was proposed for the determination of the heat transfer coefficient on the active surface of the thick-walled plate. The temperature and heat flux on the exposed surface were obtained by measuring the unsteady temperature in a small region on the insulated external surface of a pressure component that is easily accessible. Three different procedures for the determination of the heat transfer coefficient on the water-spray surface were presented, with the division of the plate into three or four finite volumes in the normal direction to the plate surface. Calculation and experimental tests were carried out in order to validate the method. The results of the measurements and calculations agreed very well. The computer calculation time is short, so the technique can be used for online stress determination. The proposed method can be applied to monitor thermal stresses in the components of the power unit in thermal power plants, both conventional and nuclear.

Three-Dimensional Surface Heat Transfer Coefficient and Thermal Stress Analysis for Ceramics Tube Dipping into Molten Metal

2010 ◽  
Vol 452-453 ◽  
pp. 233-236 ◽  
Author(s):  
Yasushi Takase ◽  
Wen Bin Li ◽  
Hendra ◽  
Hiroki Ogura ◽  
Yusuke Higashi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Stress ◽  
Transfer Coefficient ◽  
Molten Metal ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Surface Heat ◽  
Surface Heat Transfer ◽  
Surface Heat Transfer Coefficient

The low pressure die casting machine has been used in industries because of its low-cost and high efficiency precision forming technique. In the low pressure die casting process is that the permanent die and filling systems are placed over the furnace containing the molten alloy. The filling of the cavity is obtained by forcing the molten metal, by means of a pressurized gas, to rise into a ceramic tube, which connects the die to the furnace. The ceramics tube, called stalk, has high temperature resistance and high corrosion resistance. However, attention should be paid to the thermal stress when the ceramics tube is dipped into the molten metal. It is important to reduce the risk of fracture that may happen due to the thermal stresses. To calculate the thermal stress, it is necessary to know the surface heat transfer coefficient when the ceramics tube dips into the molten metal. In this paper, therefore, the three-dimensional thermo-fluid analysis is performed to calculate surface heat transfer coefficient correctly. The finite element method is applied to calculate the thermal stresses when the tube is dipped into the crucible with varying dipping speeds and dipping directions. It is found that the thermal stress can be reduced by dipping slowly when the tube is dipped into the molten metal.

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